Two-thirds of cities experiencing relative economic decline face above average flood disadvantage according to new research by Sayers and Partners for the Joseph Rowntree Foundation.

The report, Present and future flood vulnerability, risk and disadvantage: A UK assessment highlights how floods interact with social vulnerability across the UK to create flood disadvantage, an issue which will be exacerbated by climate change.

Today some 6.4 million people live in flood prone areas, with around 1.5 million of these people living in vulnerable neighbourhoods (which include people on low incomes, with poor health and other factors that means floods are likely to have more negative impacts on people). According to the research, over 50% of the population exposed to flooding in the most vulnerable neighbourhoods can be found in just ten local authorities.

The number of people living in flood prone areas is set to increase to 10.8 million people by the 2080s, assuming a plausible but more extreme future scenario (of high population growth and a 4 degree centigrade increase in temperatures due to climate change).Cities in relative economic decline experience levels of flood disadvantage above the UK average, suggesting floods could undermine economic growth in areas that need it most and lead to a spiral of decline if repeated floods occur.

Recent developments are also facing increasing risk. Of the 300,000 properties built in the most socially vulnerable neighbourhoods between 2008-14, nearly 14% are in areas prone to fluvial or coastal flooding. By the 2080s, those living in these developments will experience a disproportional increase in flood risk compared to new developments built elsewhere in the floodplain. This is especially the case where new developments have taken place in socially vulnerable coastal communities.

The report highlights a series of recommendations for policymakers including:

Adopt new indicators to highlight the risks faced by the most socially vulnerable (including a new Neighbourhood Flood Vulnerability Index (NFVI), a Social Flood Risk Index (SFRI) and a measure of Relative Economic Pain (REP)

Use these new indicators to better target support for the most socially vulnerable in flood investment decisions.